title: A new 4-nitrotoluene degradation pathway in a Mycobacterium strain.
abstract: Mycobacterium sp. strain HL 4-NT-1, isolated from a mixed soil sample from the Stuttgart area, utilized 4-nitrotoluene as the sole source of nitrogen, carbon, and energy. Under aerobic conditions, resting cells of the Mycobacterium strain metabolized 4-nitrotoluene with concomitant release of small amounts of ammonia; under anaerobic conditions, 4-nitrotoluene was completely converted to 6-amino-m-cresol. 4-Hydroxylaminotoluene was converted to 6-amino-m-cresol by cell extracts and thus could be confirmed as the initial metabolite in the degradative pathway. This enzymatic equivalent to the acid-catalyzed Bamberger rearrangement requires neither cofactors nor oxygen. In the same crucial enzymatic step, the homologous substrate hydroxylaminobenzene was rearranged to 2-aminophenol. Abiotic oxidative dimerization of 6-amino-m-cresol, observed during growth of the Mycobacterium strain, yielded a yellow dihydrophenoxazinone. Another yellow metabolite (lambda max, 385 nm) was tentatively identified as 2-amino-5-methylmuconic semialdehyde, formed from 6-amino-m-cresol by meta ring cleavage.
authors.affiliation: Fraunhofer Institut für Grenzflächen- und Bioverfahrenstechnik, Stuttgart, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Spiess
authors.forename: F
authors.initials: F
authors.lastname: Desiere
authors.forename: P
authors.initials: P
authors.lastname: Fischer
authors.forename: J C
authors.initials: JC
authors.lastname: Spain
authors.forename: H J
authors.initials: HJ
authors.lastname: Knackmuss
authors.forename: H
authors.initials: H
authors.lastname: Lenke
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D009161:Mycobacterium / Q000254:growth & development / Q000378:metabolism*; D014050:Toluene / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D014050:Toluene; C017572:4-nitrotoluene